Braking device



Nov. 22, 1927.

E. G. GARTIN BRAKING DEVICE Filed Jan. 10 1921 171,!) 7". 1 er 7r? 1 Patented Nov. 22, 1927.

' :aLMER G. GARTIN,

or Grammar, NEW, HAMPSHIRE, ASSIGNOR TO 'sUL IveN MACHINERY COMPANY, A co PoRArIoN or MASSACHUSETTS. I

' BRAKING DEVICE.

Applicatigm filed Jan uary 10, 1921; Serial No. 436,242."

My invention relates to braking devices and more particularly to braking "devices for controlling the feed of rock drilling mechanisms. Y I

An object of my invention is to rovide an improved braking device. A furt er object of my invention is to provide a simple and improved mechanism for controllingthe strength of feed of rock drilling device's.

Other objects of my invention will appear:

pended claims. H r V In the accompanying drawings Iqha-ve shown for purposes of illustration one embodiment which my invention may assume in practice. i Q

In thesedrawings- Fig. 1 is a central longitudinal section through the feed cylinder of a fluid. pressure feeding device for rock drills, parts being broken away to show internal construcin the course of the specification and the aption.

Fig. 2 is a transverse section on the line Figs. 3, 4c, and 5 are fragmentary views through the control mechanism on the same section as that of Fig. l and showing the control valve in difierent positions.

In the -illustrative embodiment of my invention, I have disclosed it used in connection with a feeding mechanism 1 of a rock drilling motor 2, the feeding mechanism comprising a. cylinder :3, having a bore 4 in which a piston 5 is reciprocable in one direction under the action of fluid pressure and in the opposite direction dueto gravity or force manually applied. The piston 5 is provided with a piston rod 6 connected to the rear head 7 of the rock drilling motor 2, and within the head 7 is arranged controlling mechanism I generally designated 8 for controllingthe operation ofthe feeding mechanism.

My improved braking mechanisni consists essentially of afriction member 9 care ried in a suitable elastic normally contracted carrier member 10 which is groovedas shown at 11 on its outer surfacefto receive the braking material. The carrier member. 10 is carried in turn in an annular, channel 12 formed in the periphery of the piston and of sufiicient depth to permit the contracted carrier member 10 when not held out toward the walls of the cylinder to contract sufiiciently to withdraw the friction material 9 from contact with the cylinderwalls in such 7 i v y .Z manner as to reduce, or entirely discontinue,

itsfrictional efiect .on the cylinder bore. To control the braking mechanism and lIkGWISB the feeding operation, I provide a control valve mechanism designatedabove as 8 and'located on the base of the drilling motorconsisting of avalve chamber13 ,pro% vided with a bushing 14 having a pair of ports 15 and 16, passing therethrough and carrying Within the bushing valve 17 1 adapted to receive pressure fluid in a central chamber 18 and to 'conductjtfby way' of ports 19-, 20, and 21 in a mannerhe'rein'after described.' f I The ports 19, 20, and 21 extend radially through the wall of the valve" 17 and are arranged in a' series in a single transverse zone about the periphery of the valve. Formed between the ports 19 and 20 is a groove23 communicating with a suitable exhaust, not shown. A passage 22 extending longitudinally. through the piston rod 6 serves to conduct the fiuid admitted-through the port 15 to therear. end of the feed cylinder 3 and causes forward feeding/of the piston 5j and of the percussive tool as a whole. A passage'24 serves to conduct pressure fluid behind the friction member 9 and so to cause braking operation thereof. 'The valve17 occupies four main positions in thecontrol of feeding mechanis n, namely, those shown in Figs. 1, 3, 4, and 5. i. Y

' (In Fig.1fthe'p0rt .15 .is shown in com munication with the exhaust port 23 and accordingly thereis nov pressure, tending to 'force thedrill motor towards :the work and also itwill be'noted that nopressure' being supplied to the passage 16 so thatthe device is not subjected to frictionin its .movements' under manual control.

In F 3 f dl bei afs pp i y way ofv port 20, passage 15 and passage 22 to the rear end of the feed cylinder and is causing forward feed ofrthe drillmotor.

In Fig. 4, fluidhas-been out 011' from the .passage22and fluid pressure is being supplied way of passage "24 behind the fric- Ytion member 9 and is retarding the feed.

In,F1g. 5, pressure is be ng supplied through the port 21 in the valve,"passage 15 and passage 22 to cause .forwa-rdfeeding of the drill motor, while the pressure. behind the friction member 9 is being reduced by means of. the fact that theexhaust port 23 ill It will be obvious that by shifting the valve between positions 4 and .5,.it will be possible to obtain a gradual feed under the control of the braking mechanism, the feed being retarded by placing the parts-in position shown in Fig. shown in Fig. 5. 7

From the foregoing description and the several views of the drawing, it is believed that the operation of this device. will be readily apparent without further detailed statement of its function.

While I have in this application specifically described one form which myinvention may assume in practice, it'will' be un derstood that this form of the same is shown for purposes of illustration and that the ini and accelerated in that vention may be modified and embodied in other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is l..- Drill feeding mechanism comprising a pair of telescopically related members having a range of relative movement greater than the length of the shorter one of said members and substantially equal to the difference in lengths of said members, means for effecting movement of one member relative to the other, means for causing variable friction between said members comprising an elastic annular brake carried by the moving one of said members and eXpansible by fluid pressure into engagement with the other, and unitary means operable at will to admit pressure fluid to said brake individually or to vent same. i

2. Drill feeding mechanism comprising a pair of telescopically/related members, means actuated by pressure fluid for mov- .ing one member on the vother, means for causing variable braking action between said members comprising an elastic annular brake carried by one of said members and e'xpansible by fluid pressure into engagement with the other, means for expanding said brake, by admitting pressure fluid thereto independently of fluid supply to said telescopically related members, and a common control valve movable with said movable feeding member for both the feeding and braking means. v

Drill feeding mechanism comprising a pair of telescopically related members, means actuated by pressure fluid for moving one member on the other, means for causing variablebraking action between said members comprising an elastic annular brake carried by the inner oneof said members and expansible by fluid pressure into engage'ment with the other, means for expanding said brake by admitting pressure fluid thereto individually, and common control means for both the feeding and braking means comprising separate conduits in the inner member controlled by a single valve.

l, Drill feeding mechanism comprising acylinder, a piston'comprising a head and rod reciprocable in the cylinder, said head being reciprocable in said cylinder in a path of greater length than its own length and 'reciprocable in the cylinder, 2 an annular brake band carried by said piston head in position to engage the cylinder -wall-and having a chamber provided behind it, and means individual thereto for admitting pressure fluid to said chamber at will comprismg a conduit in said piston rodcontrolled bya hand operated valve.

ill)

6. Drill feeding mechanism comprising a cylinder, a piston comprising a head and rod reciprocable 1n the cylinder, means for admitting pressure fluid to sald cylinder comprising a conduit in said piston, an annular brake band carried by said piston head in position to engage the cylinder wall and having a chamber providedbehind it, means for admitting pressure fluid to said chamber comprising a second conduit in said piston, and a hand operated valve common to both said'conduits. a 1. I

7. Drill feeding mechanism comprising a cylinder, a piston comprising a head and rod reciprocable in the cylinder, means for. admitting pressure fluid to said cylinder comprising a conduit in-said rod, an annular brake band carried by said piston head inposition to engage the cylinder wall and having achamber providedfbehind it, means for admitting pressure fluid to said chamber comprising a second conduit in. said rod, means for venting the brake and feed, anda hand operated valve having means for selectively supplying pressure fluid to either conduit alone or to both together and'for vent}.

ing the same.v

8'. Drill feedingmechanism comprising a cylinder, a: piston movable therein by, pressure fluid, a brake carried by said piston and movable radially thereof under the direct action of pressure fluid, control means comprising 'conduitsformed. in said piston and individual to said cylinder and bralreirespecand" means for admitting g fluid thereto selectively;

9. Drill feeding mechanism comprising. a

cylinder,a piston movable therein by pressure fluid, a'brake carried bysaid piston and lit) tively movable into communication with either conduit alone or with both conduits at once. I

10. Drill feeding mechanism comprising a cylinder, a. piston movable therein by pressure fluid, a brake carried by said piston and movable radially thereof under the direct action of pressure fluid, means comprising conduits formed in said piston and inclividual to said cylinder and brake respectively for admitting pressure fluid thereto, a single valve provided with ports selectively movable into communication with either conduit alone or with both conduits at once, and means also controlled by said valve for venting the cylinder and brake.

l1. Drill feeding mechanism comprising a cylinder, a piston movable therein by pressure fluid, a pressure fluid brake carried by the piston and engageable with the cylinder wall, and means including unitary valve mechanism operable at will to control the flow of pressure fluid to the piston' or brake individually.

12. Drill feeding mechanism comprising cylinder and piston elements relatively movable by pressure? fluid, a drill actuating motor carried by and movable with one of said elements, a brake carried by the piston and engageable with the cylinder 'wall,

.means for actuating the brake comprising power transmitting means extendin longitudinally in the piston, and'means or controlling transmission of' power thereby to the brake located at the base of said drill actuating motor and movable therewith.

13. Drill feeding mechanism comprising a feedcylinder, a'feed piston therein, said cylinder and piston arranged to perm-it relative movement of greater extent than the length of the piston, radially expansible friction brake means and means for expanding the same carried bysaid piston, means for admitting fluid to effect relative movement between the cylinder and piston, and means operative either when such fluid admission is occurring or interrupted for" controlling said friction brake.

In testimony whereof I aflix my signature.

ELMER G. GARTIN. 

